Following a battle with the Brood in space, members of the Fantastic Four and the X-Men were bombarded by cosmic rays before crash landing in Upstate New York. Now the rest of the two groups are frantically searching for their missing teammates as there is concern how the cosmic rays could affect the mutant physiology of the X-Men. As they squabble over the situation, they are suddenly interrupted when Wolverine's claws stretch up from the forest and puncture through the Fantasti-Car. They are then attacked by kinetic fire balls lobbed at them by Gambit. They quickly realize that they are being attacked by the four members of the X-Men that were on the mission -- Wolverine, Gambit, Emma Frost and Nightcrawler -- who have been further mutated with similar powers to the Fantastic Four.

They quickly realize that the X-Men are not in their proper state of mind soon have to fight off their own friends. With Wolverine's elastic body, Nightcrawler's newfound invisibility, Gambit's flame powers, and Emma having been transformed into a She-Thing, the unaffected members of the X-Men and the Fantastic Four have their hands full. During the battle, Mister Fantastic notes how the X-Men all have powers similar to their own, leading him to believe their transformations into the Fantastic Four were not random occurrences. When Sue and Ben recover from the crash they join the fight and assist in knocking out Emma, Nightcrawler, and Gambit, but Wolverine manages to escape.

The captured X-Men are taken back to the Xavier Institute where the others also can use Cerebra to track down Wolverine. In the Beast's lab, the three mutated X-Men are placed in stasis so Reed and the Beast can work on reversing these radiation induced transformations, which prove to be an easy task as McCoy has the DNA profiles of every member of the X-Men, as well as the new information gleaned from Emma's secondary mutation. However in the middle of their work they are interrupted by Storm who informs them that a space shuttle has taken off from the space station Simulacrum and is heading toward New York City. On board the shuttle are the crew who have fully transformed into members of the Brood.

Notes

Continuity Notes

Reed theorises that the mutation of the X-Men are similar to the Fantastic Four because the nature of their mutations were not random. There have been evidence of the contrary, such as when the Red Ghost and his Super-Apes were mutated by cosmic rays in Fantastic Four #13 or the U-Foes were mutated by cosmic rays in Incredible Hulk #254 and were given different powers. However the idea that the Fantastic Four's powers were not random were explored further upon the group's meeting of the Entity in Fantastic Four #530, shortly after this story.

Mention is made of Emma Frost's secondary mutation, mutants have been undergoing secondary mutations since New X-Men #114. It's interesting to point out that during this conversation Mister Fantastic doesn't seem to notice that the Beast has also undergone this secondary mutation phase, nor does he bring it up.

Solicit Synopsis:

It's the X-Men and Fantastic Four versus...the X-Men and Fantastic Four?!

An unexpected adversary turns Marvel's two greatest hero families against one another.